This invention relates to exercising equipment in which the energy absorber is a vaned fanwheel rotatably mounted on the frame. This equipment takes many forms, beneficially developing and keeping in tone particular groups of muscles which are used in traditional exercising activities such as biking, rowing, swimming, cross-country skiing, and stair climbing. The work done by a group of muscles can be measured simply and accurately under controlled conditions by a speedometer connected to the fanwheel calibrated in watts, horsepower, foot pounds per minute, gram calories per minute or other suitable ergometric readouts. In this application, the invention is described for use with a cycle exerciser, but this is by way of illustration and not by way of limitation.
Exercising equipment in which the energy absorber is a vaned fanwheel is shown in Hooper U.S. Pat. No. 4,537,396 where the energy absorber is a volute fan. Applications described in that patent include a swimming machine (FIG. 1), a rowing machine (FIG. 7), a weight lifting machine (FIG. 8), leg exercising machines (FIGS. 9 and 10), and a stationary cycle machine (FIG. 11). In another Hooper U.S. Pat. No. 4,188,030, the energy absorber is a vaned fanwheel having flat blade vanes.
Daleabout U.S. Pat. Nos. 4,971,316 and 5,000,444 show fanwheel energy absorbers using conventional flat blade vanes applied to stationary cycle type exercisers. Lo U.S. Pat. No. 4,934,688 shows flat blade vanes (FIG. 8). Baldwin U.S. Pat. No. 4,589,656 shows a pair of squirrel cage fans 18a and 18b (FIGS. 6 and 7). Chang U.S. Pat. Nos. 4,961,570 and 4,962,925 show flat blade vanes applied respectively to a climber exerciser and a stationary cycle exerciser. Uhl U.S. Pat. No. 3,979,113 shows flat blade vanes in a stationary cycle exerciser. And Coffey U.S. Pat. No. 4,743,011 shows flat blade vanes applied to a rowing exercise machine.
In the air resistance exercisers shown in the above patents, and in most air resistance exercisers that are available in the retail marketplace, air resistance is obtained by a large fan-like wheel of some sort. These are generally nothing more than modified bicycle wheels or plastic molded counterparts of similar configuration. In all cases, the fanwheels are by far the largest single component of the exerciser. A drawback is that a large wheel takes a large safety guard which in turn makes the entire exerciser bigger, heavier and more expensive.
In these conventional fanwheels, the air vanes are flat plates, or as in the case of the squirrel cage rotors shown in U.S. Pat. Nos. 4,537,396 and 4,589,656, are essentially flat plates set so close together in volute casings that they are in drafting relationship and highly ineffective compared with the present invention.
With a first flat plate moving flatwise through air, a long wake is produced behind the plate. When a second flat plate is positioned within the wake of the first, it is in a stagnant air region or a partial vacuum and is said to be in "drafting" relation with the first plate and the effectiveness of the fan as an energy absorber is greatly diminished.
Thus, in conventional air vane energy absorbers, there is considerable room for improvement in reducing the size of the fan wheel and increasing its energy absorbing efficiency.